A marketplace of colorful stalls will take over one of Sacramento's busiest corners Saturday. Like an oasis in a concrete desert, a new public market called the Midtown Bazaar will spring up on a parking lot at 16th and J streets — across from the Memorial Auditorium and P.F. Chang's China Bistro — and flow through an alley into a cavernous old building for a few hours each week. At least 75 local vendors offering art and other goods have already signed up for the grand opening, to be held from 7 a.m. to 1 p.m. With an indoor location measuring 25,600 feet, the market will be held year-round. The old garage at 1630 I St. sports old timber trusses, a mezzanine and roll-up doors in back th